MITSUBISHI ELECTRIC PEFY-P12NMAU-E3 (01) PDF DOCUMENT

Before installation and performing electrical work, you must thoroughly read and observe the following safety precautions for your safety.

WARNINGS:

• Do not use refrigerant other than the type indicated in the manuals and on the nameplate (R410A). Doing so may cause the unit or pipes to burst, or result in explosion or fire.

• Ask your dealer or a qualified technician to install the unit. Improper installation may result in water leakage, electric shock, or fire.

• Properly install the unit on a surface that can withstand its weight. An unstable surface may cause the unit to fall, resulting in injury.

• Only use specified cables. Securely connect each cable so that the terminals do not carry the weight of the cable. Improperly connected cables may produce heat and start a fire.

• Take appropriate safety measures against wind gusts and earthquakes to prevent the unit from toppling over.

• Only use accessories (e.g., air cleaners, humidifiers, electric heaters) recommended by Mitsubishi Electric.

• Do not make any modifications or alterations to the unit. Improper repair may result in water leakage, electric shock, or fire.

• Do not touch the heat exchanger fins with bare hands as they are sharp and pose a risk of cuts.

• In the event of a refrigerant leak, thoroughly ventilate the room. If gaseous refrigerant leaks and contacts an open flame, toxic gases will be generated.

• Properly install the unit according to the instructions in the Installation Manual to prevent water leakage, electric shock, or fire.

• Have all electrical work performed by an authorized electrician according to local regulations and the instructions in this manual. Use a dedicated circuit.

• Keep electrical parts away from water. Wet electrical parts pose a risk of electric shock, smoke, or fire.

• Securely attach the control box cover to prevent dust or water from infiltrating, which could cause electric shock, smoke, or fire.

• Only use the indicated type of refrigerant when installing or relocating the unit. Infiltration of other substances may adversely affect the refrigerant cycle and cause pipes to burst or explode.

• When installing in a small space, take precautions to prevent leaked refrigerant from reaching the limiting concentration, which can cause oxygen starvation.

• Consult your dealer or a qualified technician when moving or reinstalling the unit.

• After completing service work, check for a refrigerant leak.

• Do not try to defeat the safety features of the unit, such as the pressure switch or temperature switch.

• Consult your dealer for proper disposal method.

• Do not use a leak detection additive.

CAUTION:

• Do not use the existing refrigerant piping. Residual chlorine in old piping can cause the new unit’s refrigerator oil to deteriorate.

• Only use R410A refrigerant. Using other refrigerants containing chloride may cause the refrigerator oil to deteriorate.

• Use refrigerant piping materials made of phosphorus deoxidized copper. Keep pipe surfaces clean and free of contaminants like sulfur, oxides, dust, dirt, oil, and moisture.

• Use a vacuum pump with a check valve to prevent vacuum pump oil from flowing into the refrigerant cycle.

• Store piping materials indoors and keep both ends sealed until brazing.

• Prepare tools for exclusive use with R410A. Do not use tools (gauge manifold, charging hose, gas leak detector, etc.) that have been used with conventional refrigerants.

• Use a small amount of ester oil, ether oil, or alkyl benzene to coat flares and flanges. A large amount of mineral oil can cause refrigerator oil to deteriorate.

• Do not use a charging cylinder, as it can alter the composition of the refrigerant.

• Charge the system with refrigerant in the liquid phase. Drawing gaseous refrigerant first will change the composition of the remaining refrigerant in the cylinder.

• Exercise special care when handling tools for use with R410A to prevent infiltration of dust, dirt, or water into the system.

Model	Cooling capacity/Heating capacity (BTU/h)	Cooling capacity/Heating capacity (kW)
PEFY-P06NMAU-E3	6000/6700	1.8/2.0
PEFY-P08NMAU-E3	8000/9000	2.3/2.6
PEFY-P12NMAU-E3	12000/13500	3.5/4.0
PEFY-P15NMAU-E3	15000/17000	4.4/5.0
PEFY-P18NMAU-E3	18000/20000	5.3/5.9
PEFY-P24NMAU-E3	24000/27000	7.0/7.9
PEFY-P27NMAU-E3	27000/30000	7.9/8.8
PEFY-P30NMAU-E3	30000/34000	8.8/10.0
PEFY-P36NMAU-E3	36000/40000	10.6/11.7
PEFY-P48NMAU-E3	48000/54000	14.1/15.8
PEFY-P54NMAU-E3	54000/60000	15.8/17.6

1	[Set Temperature] Button	7	[Vane Control] Button
2	[Timer Menu] Button / [Monitor/Set] Button	8	[Ventilation] Button / [Operation] Button
3	[Mode] Button / [Back] Button	9	[Check/Clear] Button
4	[Timer On/Off] Button / [Set Day] Button	10	[Test Run] Button
5	[Louver] Button / [Operation] Button	11	[Filter] Button / [ ] Button
6	[Fan Speed] Button	12	[ON/OFF] Button
13	Position of built-in room thermistor. The thermistor must be free from obstructions to ensure accurate measurement of room temperature.
14	[Set Time] Button

Note: Keep the remote controller out of direct sunlight to ensure accurate measurement of room temperature.

A: Current time/Timer time

B: Centralized control indicator

C: Timer OFF indicator

D: Timer mode indicator

E: Operation mode display (COOL, DRY, AUTO, FAN, HEAT)

F: Function mode indicator

G: Preset temperature

H: Power indicator

I: Louver swing

J: Ventilation

K: Filter sign

L: Sensor position

M: Room temperature

N: Vane setting

O: Fan speed

P: Operation lamp

Model	PEFY-P12NMAU-E3
Power source	1-phase 208/230V 60Hz
Cooling capacity (BTU/h / kW)	12,000 / 3.5
Cooling Power input / Current input	0.09 kW / 0.66/0.62 A
Heating capacity (BTU/h / kW)	13,500 / 4.0
Heating Power input / Current input	0.07 kW / 0.55/0.51 A
External dimension H x W x D (in. / mm)	9-7/8×27-9/16×28-7/8 / 250 x 700 x 732
Net weight (lbs (kg))	49(22)
FAN Type x Quantity	Sirocco fan x 1
External static press. (in.WG / Pa)	<0.14>-0.20-<0.28>-<0.40>-<0.60> / <35>-50-<70>-<100>-<150>
Motor type / output	DC motor / 0.085 kW
Airflow rate (Low-Mid-High) (cfm)	265-318-371
Sound pressure level (Low-Mid-High) (dB <A>)	28-30-34
Refrigerant control device	LEV
Connectable outdoor unit	R410A CITY MULTI
Diameter of refrigerant pipe (Liquid / Gas)	1/4 (6.35) Brazed / 1/2 (12.7) Brazed
Diameter of drain pipe	O.D. 1-1/4(32)

Note: Nominal cooling conditions are Indoor: 80°F D.B. / 67°F W.B., Outdoor: 95°F D.B. Nominal heating conditions are Indoor: 70°F D.B., Outdoor: 47°F D.B. / 43°F W.B. Pipe length is 25 ft. with 0 ft. level difference. The external static pressure is set to 0.20in. WG(50Pa) at factory shipment.

Component	Symbol	Specification
Room temperature thermistor	TH21	Resistance 0°C/15kΩ, 10°C/9.6kΩ, 20°C/6.3kΩ, 25°C/5.4kΩ, 30°C/4.3kΩ, 40°C/3.0kΩ
Liquid pipe thermistor	TH22	Resistance 0°C/15kΩ, 10°C/9.6kΩ, 20°C/6.3kΩ, 25°C/5.4kΩ, 30°C/4.3kΩ, 40°C/3.0kΩ
Gas pipe thermistor	TH23	Resistance 0°C/15kΩ, 10°C/9.6kΩ, 20°C/6.3kΩ, 25°C/5.4kΩ, 30°C/4.3kΩ, 40°C/3.0kΩ
Fuse	FUSE	250V 6.3A
Fan motor	–	8-pole, Output 85W SIC-70CW-D885-1
Linear expansion valve	LEV	12VDC Stepping motor drive port diameter ø3.2 (0~2000 pulse)
Power supply terminal block	TB2	(L1, L2, G) 250V 20A
Transmission terminal block	TB5, TB15	(1, 2) 250V 15A, (M1, M2, S) 250V 20A
Drain float switch	DS	Open/short detection. Initial contact resistance 500 mΩ or less

How to operate:

1. Press the POWER [ON/OFF] button.

2. Press the operation [Mode] button to display COOL.

3. Press the [Set Temperature] button to set the desired temperature (67°F to 87°F).

Thermoregulating Function:

The unit uses a 3-minute restart prevention timer.

• Thermo ON: Room temperature ≥ desired temperature + 2°F

• Thermo OFF: Room temperature ≤ desired temperature

Anti-Freezing Control:

This control activates if the liquid pipe temperature (TH22) is 33.8°F or less for 16 minutes after the compressor starts. The control is cancelled when the liquid pipe temperature rises to 50°F or above, thermoregulating turns off, the mode is changed, or the unit is stopped.

Fan Control:

You can select from 3 speeds ([Low], [Med], [High]) or [Auto]. In [Auto] mode, the fan speed changes based on the difference between the room temperature and the desired temperature.

Drain Pump Control:

The drain pump is always ON during COOL and DRY operations. When the mode is changed from COOL or DRY, the drain pump continues to run for 3 minutes before turning OFF.

Float Switch Control:

The control detects water if the float switch is ON for 15 seconds.

How to operate:

1. Press the POWER [ON/OFF] button.

2. Press the operation [Mode] button to display DRY.

3. Press the [Set Temperature] button to set the desired temperature (67°F to 87°F).

Thermoregulating Function:

The unit uses a 3-minute restart prevention timer.

• Dry thermo ON: Room temperature ≥ desired temperature + 2°F

• Dry thermo OFF: Room temperature ≤ desired temperature

The ON/OFF time of the dry thermo depends on the room temperature after 3 minutes of operation, as shown in the table below:

Room temperature	Thermo regulating signal	Room temperature (T1)	Dry thermo ON time (min)	Dry thermo OFF time (min)
Over 64°F	ON	T1 ≥ 83°F	9	3
		83°F > T1 ≥ 79°F	7	3
		79°F > T1 ≥ 75°F	5	3
		75°F > T1	3	3
	OFF	Unconditional	3	10
Less than 64°F	Dry thermo OFF

Fan Control:

The indoor fan operation depends on the compressor conditions.

• When Dry thermo is ON, the fan speed is [Low].

• When Dry thermo is OFF and room temp is below 64°F, the fan is at [Low].

• When Dry thermo is OFF and room temp is not below 64°F, the fan will Stop.

How to operate:

1. Press the POWER [ON/OFF] button.

2. Press the operation [Mode] button to display FAN.

Fan Control:

The fan speed is set by the remote controller. You can choose from 3 speeds ([Low], [Med], [High]) or [Auto]. When [Auto] is set, the fan speed becomes [Low].

Drain Pump Control:

The drain pump will turn ON for a specified time under these conditions:

• For 3 minutes after switching from COOL or DRY mode to FAN mode.

• For 6 minutes after the float switch is submerged in water.

How to operate:

1. Press the POWER [ON/OFF] button.

2. Press the operation [Mode] button to display HEAT.

3. Press the [Set Temperature] button to set the desired temperature (63°F to 83°F).

Display Indicators:

• [DEFROST] is displayed during the defrost operation.

• [STANDBY] is displayed during the hot adjust mode.

Thermoregulating Function:

The unit uses a 3-minute restart prevention timer.

• Thermo ON: Room temperature ≤ desired temperature – 2°F

• Thermo OFF: Room temperature ≥ desired temperature

Fan Control:

You can select from 3 speeds ([Low], [Med], [High]) or [Auto]. In [Auto] mode, fan speed is based on the difference between desired and room temperature. The fan control gives priority to the following modes in order: Hot adjust, Preheating exclusion, Thermo OFF, Cool air prevention (Defrosting), and Capacity increasing.

Hot Adjust Mode:

The fan operates at [Extra Low] speed when HEAT operation starts, after thermoregulating turns ON, or after defrosting. After 5 minutes, or if the indoor liquid pipe temperature reaches 95°F or more, the fan will switch to the speed set by the remote controller. The “STAND BY” icon is displayed during this mode.

Thermo OFF Mode:

When thermoregulating changes to OFF, the indoor fan operates in [Extra low].

Heat Defrosting Mode:

The indoor fan stops during defrosting.

How to operate:

1. Press POWER [ON/OFF] button.

2. Press the operation [Mode] button to display AUTO.

3. Press the [Set Temperature] button to set the desired temperature (67°F to 83°F).

Initial Operation Mode:

• If the room temperature is less than the desired temperature, the unit will start in HEAT mode.

• If the room temperature is greater than or equal to the desired temperature, the unit will start in COOL mode.

Mode Change:

• HEAT mode to COOL mode: Switches when the room temperature is greater than the desired temperature + 3°F for 3 minutes or more.

• COOL mode to HEAT mode: Switches when the room temperature is less than or equal to the desired temperature – 3°F for 3 minutes or more.

The control logic for COOL and HEAT modes is the same as their respective manual operation modes.

(1) Thermistor Check (TH21, TH22, TH23):

Disconnect the thermistor connector and measure the resistance. At an ambient temperature of 10°C – 30°C (50°F – 86°F), the normal resistance should be between 4.3 kΩ and 9.6 kΩ. If it’s open or short, it’s abnormal.

Reference values:

• 0°C (32°F): 15 kΩ

• 10°C (50°F): 9.6 kΩ

• 20°C (68°F): 6.3 kΩ

• 30°C (86°F): 4.3 kΩ

(2) Linear Expansion Valve (LEV) Check:

Disconnect the connector and measure the resistance between the terminals. The normal resistance between the coil pairs (White-Red, Yellow-Brown, Orange-Red, Blue-Brown) should be 200 Ω ±10%.

LEV Troubleshooting:

Symptom	Checking Criteria	Remedy
Circuit failure on the microcomputer	Disconnect the connectors on the control board and connect LEDs to test the circuit. Pulse signals are output for 10 seconds when power is turned on. If LEDs do not light up or remain lit after pulses are turned off, there is a problem with the driving circuit.	Replace the indoor control board if driving circuit failure is detected.
Locked LEV	The motor will idle and make a small clicking noise if run while locked. If this noise is heard both when the valve is fully closed and opening, it indicates a problem.	Replace the LEV.
Disconnected or shorted LEV motor coils	Measure the resistance between the coils with a tester (red-white, red-orange, brown-yellow, brown-blue). The normal range of resistance is 200 Ω±10%.	Replace the LEV.
Valve closure failure (leaky valve)	Check the indoor unit liquid pipe temperature on the outdoor unit’s monitor while operating the unit in FAN mode and other units in COOL mode. Normally, the LEV is fully closed. If the liquid pipe thermistor reading is significantly lower than the inlet temperature, a leaky valve is suspected.	Replace the LEV if the amount of leakage is great.

(3) Drain-up Mechanism Check:

Measure the resistance between terminals 1 and 3 of the drain pump connector. At a coil temperature of 20°C (68°F), the normal resistance is 340 Ω. Open or short indicates a problem.

(4) Drain Float Switch Check (CN4F):

Disconnect the connector and measure resistance.

• When the moving part is UP: Short circuit (normal).

• When the moving part is DOWN: Open circuit (normal).

Symptom: Indoor unit fan does not run.

CAUTION: A high voltage is applied to the fan motor connector (CNMF). Do not unplug it with the unit energized.

1. Check if the fan motor connector (CNMF) is fully inserted. If not, fix the connection.

2. If the connector is secure, check the power supply voltages at the indoor control board:

• VDC (between fan connector 1 (+) and 4(-)): Should be between 294-340VDC depending on power supply (e.g., 294VDC for 208VAC, 325VDC for 230VAC).

• Vcc (between fan connector 5 (+) and 4(-)): Should be 15VDC.

• Vsp (between fan connector 6 (+) and 4(-)): Should be 1-6.5VDC during operation and 0V when stopped.

3. If the voltages are not within the normal range, replace the indoor control board.

4. If voltages are normal, check the fan motor position thermistor signal (VFG). Get the motor to make a full rotation or more and measure the voltage between fan connector 7 (+) and 4(-).

5. The voltage should alternate between 0VDC and 15VDC. If it does not, replace the motor.

6. If the voltage alternates correctly, replace the indoor control board.

Make sure the power to the unit is turned off before setting the address.

1. When using an ME remote controller, set the address with the rotary switches (SW11 for 1’s digit, SW12 for 10’s digit). Address setting is required for the indoor units to run.

2. Address setting is not required when a unit remote controller is used.

3. The address is set by combining SW12 and SW11. For example:

• To set address “3”, set SW12 to “0” and SW11 to “3”.

• To set address “25”, set SW12 to “2” and SW11 to “5”.

Refer to the outdoor unit installation manual for specific address settings required by your system.

Dipswitch settings must be made while the unit is stopped. Changes to SW1, SW2, and SW3 become effective when the remote controller is turned OFF. Changes to SW11, SW12, and SW14 require the unit to be stopped and the remote controller OFF.

SW1: Function setting

Switch	Function	ON	OFF (Factory Setting)
1	Active Thermistor (Intake air thermistor)	Built-in thermistor on the remote controller	Indoor unit
2	Filter clogging detection	Available	Unavailable
3	Filter life	2500 hr	100 hr
4	Outdoor air intake	Enabled	Disabled
5	Remote display	Thermo-ON signal	Fan output
6	Humidifier operation	During heating mode	During heating operation
7	Fan speed	Low	Very low
8	Fan speed at heating Thermo-OFF	Preset fan speed	Follows the setting of SW1-7
9	Auto restart after power failure	Enabled	Disabled
10	Power start/stop	Enabled	Disabled

SW3: Model setting

Switch	Function	ON (Factory Setting)	OFF
1	Unit type	–	Cooling only
4	Heater backup	Enabled	Disabled
8	Heating 4-deg up	Disabled	Enabled

For model PEFY-P12NMAU-E3, SW3-1 is ON and SW3-2 is ON at the factory.

SW2: Capacity code setting

For PEFY-P12NMAU-E3, the factory setting is SW2-3 and SW2-4 set to ON.

SW4: Model setting

For PEFY-P12NMAU-E3, the factory setting is SW4-1 set to ON.

SW5: Power voltage setting

This must be operated with the main power turned OFF. The factory setting is 240V (230V). Set to 220V (208V) side for a 208 volts power supply.

SWA, SWC: External static pressure

These switches can be changed while the unit is running. The factory setting is 50Pa (0.20in.WG).

SW11, SW12 (Rotary switch): Address setting

Sets the unit address (1s and 10s digits).

SW14 (Rotary switch): Connection No. setting

Used when connected to an R2 series outdoor unit.

Exercise caution when removing heavy parts.

1. Control Box

• Remove the three fixing screws on the control box cover to remove it. Tighten screws to a torque of 2.0±0.2 N.m.

2. Thermistor (Intake Air)

• After removing the control box cover, pull out the thermistor holder and thermistor from the control box.

3. Drainpan

• Push down the tab on the filter and pull it out.

• Remove the fixing screws on the bottom plate to remove it. Tighten screws to a torque of 1.4±0.2 N.m.

• Drain any water out of the drain pan before pulling it out.

4. Thermistor (Gas pipe / Liquid pipe)

• Remove the drain pan first.

• Remove the four fixing screws on the heat exchanger cover to remove it. Tighten screws to 1.4±0.2 N.m.

• Remove the thermistor from the thermistor holder on the copper tube.

5. Fan and Fan Motor

• Remove the filter and bottom plate.

• Squeeze the tabs on the bottom half of the fan casing to remove it.

• Remove the motor cable from the rubber bush.

• Remove the two motor fixing screws to remove the motor and Sirocco fan. Tighten screws to 3.5±0.2 N.m.

• Remove the four fan case fixing screws to take the top half of the fan casing off. Tighten screws to 1.4±0.2 N.m.

6. Heat Exchanger

• Remove the drain pan.

• Remove the heat exchanger cover.

• Remove the five fixing screws on the cover (pipe support plate) to remove it. Tighten screws to 2.0±0.2 N.m.

• Remove the fixing screws on the heat exchanger itself to remove it. Tighten screws to 1.4±0.2 N.m.